Ice flow dynamics of the northwestern Laurentide Ice Sheet during the last deglaciation

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F25%3A10499043" target="_blank" >RIV/00216208:11310/25:10499043 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=sSM9co3RbX" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=sSM9co3RbX</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5194/tc-19-869-2025" target="_blank" >10.5194/tc-19-869-2025</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Ice flow dynamics of the northwestern Laurentide Ice Sheet during the last deglaciation

Popis výsledku v původním jazyce

Reconstructions of palaeo-ice-stream activity provide insight into the processes governing ice stream evolution over millennial timescales. The northwestern sector of the Laurentide Ice Sheet experienced a period of rapid retreat driven by warming during the B &amp; oslash;lling-Aller &amp; oslash;d (14.7-12.9 ka) that may have contributed significantly to global mean sea level rise during this time. Therefore, the northwestern Laurentide Ice Sheet provides an opportunity to investigate ice sheet dynamics during a phase of rapid ice sheet retreat. Here, we classify coherent groups of ice-flow-parallel lineations into 326 flowsets and then categorise them as ice stream, deglacial, inferred deglacial or event flowsets. Combined with ice-marginal landforms and a new ice margin chronology (Dalton et al., 2023), we present the first reconstruction of ice flow dynamics of the northwestern Laurentide Ice Sheet at 500-year time steps through the last deglaciation (17.5-10.5 ka). At the local Last Glacial Maximum (17.5 ka), the ice stream network was dominated by large, marine-terminating ice streams (&gt; 1000 km long) that were fed by the Cordilleran-Laurentide ice saddle to the south and the Keewatin Dome to the east. As the ice margin retreated onshore, the drainage network was characterised by shorter, land-terminating ice streams (&lt; 200 km long), with the exception of the Bear Lake and Great Slave Lake ice streams (similar to 600 km long) that terminated in large glacial lakes. Rapid reorganisation of the ice drainage network, from predominantly northerly ice flow to westerly ice flow, occurred over similar to 2000 years, coinciding with a period of rapid ice sheet surface lowering in the ice saddle region. We note a peak in ice stream activity during the B &amp; oslash;lling-Aller &amp; oslash;d that we suggest is a result of increased ablation and a steepening of the ice surface slope in ice stream onset zones and the increase in driving stresses that contributed to rapid ice drawdown. The subsequent cessation of ice stream activity by the end of the B &amp; oslash;lling-Aller &amp; oslash;d was a result of ice drawdown lowering the ice surface profile, reducing driving stresses and leading to widespread ice stream shutdown.

Název v anglickém jazyce

Ice flow dynamics of the northwestern Laurentide Ice Sheet during the last deglaciation

Popis výsledku anglicky

Reconstructions of palaeo-ice-stream activity provide insight into the processes governing ice stream evolution over millennial timescales. The northwestern sector of the Laurentide Ice Sheet experienced a period of rapid retreat driven by warming during the B &amp; oslash;lling-Aller &amp; oslash;d (14.7-12.9 ka) that may have contributed significantly to global mean sea level rise during this time. Therefore, the northwestern Laurentide Ice Sheet provides an opportunity to investigate ice sheet dynamics during a phase of rapid ice sheet retreat. Here, we classify coherent groups of ice-flow-parallel lineations into 326 flowsets and then categorise them as ice stream, deglacial, inferred deglacial or event flowsets. Combined with ice-marginal landforms and a new ice margin chronology (Dalton et al., 2023), we present the first reconstruction of ice flow dynamics of the northwestern Laurentide Ice Sheet at 500-year time steps through the last deglaciation (17.5-10.5 ka). At the local Last Glacial Maximum (17.5 ka), the ice stream network was dominated by large, marine-terminating ice streams (&gt; 1000 km long) that were fed by the Cordilleran-Laurentide ice saddle to the south and the Keewatin Dome to the east. As the ice margin retreated onshore, the drainage network was characterised by shorter, land-terminating ice streams (&lt; 200 km long), with the exception of the Bear Lake and Great Slave Lake ice streams (similar to 600 km long) that terminated in large glacial lakes. Rapid reorganisation of the ice drainage network, from predominantly northerly ice flow to westerly ice flow, occurred over similar to 2000 years, coinciding with a period of rapid ice sheet surface lowering in the ice saddle region. We note a peak in ice stream activity during the B &amp; oslash;lling-Aller &amp; oslash;d that we suggest is a result of increased ablation and a steepening of the ice surface slope in ice stream onset zones and the increase in driving stresses that contributed to rapid ice drawdown. The subsequent cessation of ice stream activity by the end of the B &amp; oslash;lling-Aller &amp; oslash;d was a result of ice drawdown lowering the ice surface profile, reducing driving stresses and leading to widespread ice stream shutdown.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10508 - Physical geography

Projekt

<a href="/cs/project/EF19_073%2F0016935" target="_blank" >EF19_073/0016935: Grantová schémata na UK</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Cryosphere

ISSN

1994-0416

e-ISSN

1994-0424

Svazek periodika

19

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

42

Strana od-do

869-910

Kód UT WoS článku

001431352400001

EID výsledku v databázi Scopus

2-s2.0-85218891555